Back to results
US 6,388,416 B1Granted
Motor control device and motor control method
AssigneeSharp Kabushiki Kaisha
InventorsMasaji Nakatani, Hideshi Ohtsuka
Life of this patent
Estimating the term…
Abstract
A motor current detection amplifier detects a motor current's areas in two phase periods with reference to a motor voltage. A controlling microcomputer computed the ratio of the motor current areas of the two phase periods and provides the same as phase difference information which is in turn used to control a motor drive voltage to apply a sine wave of a predetermined period to the motor's coil to allow 180°-driving including a sine wave conduction resistant to noise and achieving a reduced cost hike.
Claims42
A motor control device for controlling a synchronous motor comprising:
- motor current detection means for detecting a motor current flowing through a coil of a synchronous motor;
- detection means for detecting phase difference information between said motor current and a drive voltage supplied to said coil;
- and
- control means for referring to said phase difference information and thereby detecting a condition of said synchronous motor, and for referring to said condition of said synchronous motor to control said drive voltage applied to a terminal of said coil and a frequency of a conduction to the terminal of said coil,
- wherein said phase difference information is a ratio between a first area of a waveform of said motor current in a first predetermined phase period of a waveform of said drive voltage and a second area of a waveform of said motor current in a second predetermined phase period of a waveform of said drive voltage.
2 more elements
A motor control device for driving and controlling a synchronous motor having a motor coil including a plurality of phase windings, comprising:
- drive wave data creation means, responsive to the issuance of an instruction to set a rotation rate, for creating drive wave data for each of said plurality of phase windings to drive said synchronous motor;
- motor current detection means for detecting a motor current in any specific one of said plurality of phase windings to output a motor current signal;
- phase difference detection means for detecting a motor drive voltage phase of said any specific phase winding from the drive wave data created by said drive wave data creation means, and for detecting a phase difference between the motor drive voltage phase of said any specific phase winding and the motor current signal output from said motor current detection means, to output phase difference information;
- phase difference control means for calculating a reference duty value for controlling the phase difference information output from said phase difference detection means to attain a target value of phase difference;
- duty value calculation means for multiplying the drive wave data of each phase winding output from said drive wave data creation means by the reference duty value output from said phase difference control means, to calculate an output duty value for each phase winding;
- and
- inverter means including a plurality of switching elements, for referring to the output duty value calculated by said duty calculation means for each phase winding, to produce a pulse-width modulated signal so as to control a conduction of each switching element to provide a conduction to each motor coil,
- wherein said phase difference detection means obtains a motor current signal area in each of two phase periods with reference to the motor drive voltage phase of said any particular phase winding, and calculates a ratio between motor current signal areas in said two phase periods and uses said area ratio as phase difference information, and
- wherein said phase difference detection means samples a motor current signal n times for each of the two phase periods with reference to said motor drive voltage and accumulates each current sample data for outputting as said motor current signal area, wherein n represents an integer no less than one.
6 more elements
A motor control device for driving and controlling a synchronous motor having a motor coil including a plurality of phase windings, comprising:
- drive wave data creation means responsive to the issuance of an instruction to set a rotation rate, for creating drive wave data for each of said plurality of phase windings to drive said synchronous motor;
- motor current detection means for detecting a motor current in any specific one of said plurality of phase windings to output a motor current signal;
- phase difference detection means for detecting a motor drive voltage phase of said any specific phase winding from the drive wave data created by said drive wave data creation means, and detecting a phase difference between the motor drive voltage phase of said any specific phase winding and the motor current signal output from said motor current detection means, to output phase difference information;
- phase difference control means for calculating a reference duty value for controlling the phase difference information output from said phase difference detection means to attain a target value;
- duty value calculation means for multiplying the drive wave data of each phase winding output from said drive wave data creation means by the reference duty value output from said phase difference control means, to calculate an output duty value for each phase winding;
- and inverter means including a plurality of switching elements, referring to the output duty value calculated by said duty calculation means for each phase winding, to produce a pulse-width modulated signal to control a conduction of each switching element so as to provide a conduction to each motor coil,
- wherein said phase difference detection means obtains a motor current signal area in each of two phase periods with reference to the motor drive voltage phase of said any particular phase winding and calculates a ratio between the motor current signal areas in said two phase periods and uses said area ratio as phase difference information;
- and wherein,
- said phase difference detection means samples at equal intervals the motor current signal in a phase period with reference to said motor drive voltage phase, and wherein said phase difference detection means refers to a rotation rate to set a sampling interval.
6 more elements
A motor control device for driving and controlling a synchronous motor having a motor coil including a plurality of phase windings, comprising:
- drive wave data creation means responsive to the issuance of an instruction to set a rotation rate, for creating drive wave data for each of said plurality of phase windings to drive said synchronous motor;
- motor current detection means for detecting a motor current in any specific one of said plurality of phase windings to output a motor current signal;
- phase difference detection means for detecting a motor drive voltage phase of said any specific phase winding from the drive wave data created by said drive wave data creation means, and detecting a phase difference between the motor drive voltage phase of said any specific phase winding and the motor current signal output from said motor current detection means, to output phase difference information;
- phase difference control means for calculating a reference duty value for controlling the phase difference information output from said phase difference detection means to attain a target value;
- duty value calculation means for multiplying the drive wave data of each phase winding output from said drive wave data creation means by the reference duty value output from said phase difference control means, to calculate an output duty value for each phase winding;
- and
- inverter means including a plurality of switching elements, referring to the output duty value calculated by said duty calculation means for each phase winding, to produce a pulse-width modulated signal to control a conduction of each switching element so as to provide a conduction to each motor coil,
- wherein said phase difference detection means obtains a motor current signal area in each of two phase periods with reference to the motor drive voltage phase of said any particular phase winding and calculates a ratio between the motor current signal areas in said two phase periods and uses said area ratio as phase difference information;
- and wherein,
- after the two phase periods start with reference to said motor drive voltage phase, a first motor current sampling operation starts at a timing set by correcting an amount of drive wave data exceeding a reference phase of drive wave data of said any particular phase winding.
7 more elements
A motor control device for driving and controlling a synchronous motor having a motor coil including a plurality of phase windings, comprising:
- drive wave data creation means responsive to the issuance of an instruction to set a rotation rate, for creating drive wave data for each of said plurality of phase windings to drive said synchronous motor;
- motor current detection means for detecting a motor current in any specific one of said plurality of phase windings to output a motor current signal;
- phase difference detection means for detecting a motor drive voltage phase of said any specific phase winding from the drive wave data created by said drive wave data creation means, and detecting a phase difference between the motor drive voltage phase of said any specific phase winding and the motor current signal output from said motor current detection means, to output phase difference information;
- phase difference control means for calculating a reference duty value for controlling the phase difference information output from said phase difference detection means to attain a target value;
- duty value calculation means for multiplying the drive wave data of each phase winding output from said drive wave data creation means by the reference duty value output from said phase difference control means, to calculate an output duty value for each phase winding;
- and
- inverter means including a plurality of switching elements, referring to the output duty value calculated by said duty calculation means for each phase winding, to produce a pulse-width modulated signal to control a conduction of each switching element so as to provide a conduction to each motor coil,
- wherein said phase difference detection means obtains a motor current signal area in each of two phase periods with reference to the motor drive voltage phase of said any particular phase winding and calculates a ratio between the motor current signal areas in said two phase periods and uses said area ratio as phase difference information, and wherein,
- said phase difference information is obtained by averaging m ratios between said motor current signal areas, wherein m represents an integer no less than one.
6 more elements
A motor control device for driving and controlling a synchronous motor having a motor coil including a plurality of phase windings, comprising:
- drive wave data creation means responsive to the issuance of an instruction to set a rotation rate, for creating drive wave data for each of said plurality of phase windings to drive said synchronous motor;
- motor current detection means for detecting a motor current in any specific one of said plurality of phase windings to output a motor current signal;
- phase difference detection means for detecting a motor drive voltage phase of said any specific phase winding from the drive wave data created by said drive wave data creation means, and detecting a phase difference between the motor drive voltage phase of said any specific phase winding and the motor current signal output from said motor current detection means, to output phase difference information;
- phase difference control means for calculating a reference duty value for controlling the phase difference information output from said phase difference detection means to attain a target value;
- duty value calculation means for multiplying the drive wave data of each phase winding output from said drive wave data creation means by the reference duty value output from said phase difference control means, to calculate an output duty value for each phase winding;
- and
- inverter means including a plurality of switching elements, referring to the output duty value calculated by said duty calculation means for each phase winding, to produce a pulse-width modulated signal to control a conduction of each switching element so as to provide a conduction to each motor coil,
- wherein said phase difference detection means obtains a motor current signal area in each of two phase periods with reference to the motor drive voltage phase of said any particular phase winding and calculates a ratio between the motor current signal areas in said two phase periods and uses said area ratio as phase difference information, and wherein,
- wherein in obtaining said phase difference information, an averaging count m is set depending on a rotation rate.
6 more elements
A method of controlling a synchronous motor by means of a control device including means for detecting a motor current flowing through a coil of said motor and means for detecting phase difference information from a ratio between a first area of a waveform of said motor current in a first predetermined phase period of a waveform of a drive voltage supplied to said coil, and a second area of said waveform of said motor current in a second predetermined phase period of said waveform of said drive voltage supplied to said coil, such that when said motor starts, said control device supplies said coil with a preselected drive voltage that is constant in conduction frequency, and with time said control device may increase said drive voltage in amplitude at a predetermined rate, and further wherein said control device refers to variations in said phase difference information among sequential drive voltage waveforms to detect over time the manner in which said motor rotates, said method comprising the steps of:
- determining that said motor is providing unsteady rotation when the detected phase difference information from a present drive voltage waveform has a significant variation from the detected phase difference information of the previous drive voltage waveform;
- and
- after said first step, determining that said motor is providing steady rotation when the detected phase difference information from a present drive voltage waveform no longer has a significant variation from the detected phase difference information of the previous drive voltage waveform.
Dependencies are inferred from the claim text.